1. Field of the Invention
The present invention relates to an electromagnetic valve that controls the supply of water and, more particularly, to an electromagnetic valve having a flow control function to control the flow rate of water and to prevent backflow.
2. Description of Related Art
Electromagnetic valves, which control the supply of water, are disposed at suitable points along a water supply pipeline that is directly connected to a water supply pipe or the like. Such an electromagnetic valve has an inlet in one portion of a body thereof, through which water supplied from the water supply pipe flows in, and an outlet in another portion of the body, through which the water flows out to a part that uses the water. A valve chest, which contains therein a valve plate, is provided in the portion of the body that is between the inlet and the outlet. The valve plate is switched between opened and closed states using a movable core, which is actuated by a magnetic force from an electromagnet, to open and close a valve seat, thereby controlling the supply of water.
Such an electromagnetic valve is required to control the flow of water, i.e. to control the flow of water so that the flow rate of water remains normal and so that water does not flow back, under the situation in which the pressure at which water is fed is irregular. The flow rate of water must be controlled, for example, when instantaneous counterpressure occurs as a counter reaction after water in the user side has stopped flowing. Otherwise, water in the user side may flow back into the valve. It is also required to control the flow rate of water in response to changes in the pressure of feed water that occurs in a raw water pipe.
Therefore, in recent days, electromagnetic valves are additionally provided in the outlet side thereof with flow control structures, which serve to prevent backflow and control the flow rate of water. Such a flow control structure elastically responds to the outflow of water. Specifically, when the supply of water is stopped, or when water in the user side has stopped flowing, the flow control structure closes a passage between a chamber and the outlet, thereby preventing the water from flowing back in. In addition, the flow control structure may be flexibly disposed in one of the inlet and the outlet, in an orientation that is perpendicular to the route of flowing water, such that it can change the area of its channel in response to changes in the pressure with which water is supplied, thereby keeping the flow of water at a regular rate.
However, such flow control requires separate structures for preventing backflow and controlling the flow rate. That is, the structure for preventing backflow and the structure for controlling the flow rate are independently fabricated. The structure for preventing backflow is disposed on the outlet side, and the structure for controlling the flow rate is separately disposed on either the inlet or outlet side.
As the flow control structures are separately disposed as above, subsidiary components are additionally provided for the installation of these structures, thereby making the structures and channels complicated. In addition, larger space is needlessly occupied, resistance to the flow of water increases, the control of the flow rate becomes unstable, and the assembly of complicated structures results in defects, thereby lowering the reliability of the product.
The information disclosed in this Background of the Invention section is only for the enhancement of understanding of the background of the invention, and should not be taken as an acknowledgment or any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.